Arthas
模拟死锁的场景
public class Deadlock {private static Object obj1 = new Object();private static Object obj2 = new Object();public static void main(String[] args) {new Thread(() -> {System.out.println("线程1执行");synchronized (obj1) {try {TimeUnit.SECONDS.sleep(1);} catch (InterruptedException e) {e.printStackTrace();}synchronized (obj2) {}}}, "t1").start();new Thread(() -> {System.out.println("线程2执行");synchronized (obj2) {synchronized (obj1) {}}}, "t2").start();System.out.println("执行完毕");}
}
通过thread命令定位
1，直接使用”thread“命令，输出线程统计信息。其中：BLOCKED 表示目前阻塞的线程数。
[arthas@11596]$ threadThreads Total: 26, NEW: 0, RUNNABLE: 8, BLOCKED: 2, WAITING: 4, TIMED_WAITING: 2, TERMINATED: 0, Internal threads: 10
ID NAME GROUP PRIORITY STATE %CPU DELTA_TIM TIME INTERRUPT DAEMON
2 Reference Handler system 10 WAITING 0.0 0.000 0:0.000 false true
3 Finalizer system 8 WAITING 0.0 0.000 0:0.000 false true
4 Signal Dispatcher system 9 RUNNABLE 0.0 0.000 0:0.000 false true
5 Attach Listener system 5 RUNNABLE 0.0 0.000 0:0.031 false true
14 arthas-timer system 5 WAITING 0.0 0.000 0:0.015 false true
17 arthas-NettyHttpTelnetBootstr system 5 RUNNABLE 0.0 0.000 0:0.015 false true
18 arthas-NettyWebsocketTtyBoots system 5 RUNNABLE 0.0 0.000 0:0.015 false true
19 arthas-NettyWebsocketTtyBoots system 5 RUNNABLE 0.0 0.000 0:0.015 false true
20 arthas-shell-server system 5 TIMED_WA 0.0 0.000 0:0.000 false true
21 arthas-session-manager system 5 TIMED_WA 0.0 0.000 0:0.000 false true
22 arthas-UserStat system 5 WAITING 0.0 0.000 0:0.000 false true
24 arthas-NettyHttpTelnetBootstr system 5 RUNNABLE 0.0 0.000 0:0.109 false true
25 arthas-command-execute system 5 RUNNABLE 0.0 0.000 0:0.015 false true
10 t1 main 5 BLOCKED 0.0 0.000 0:0.000 false false
11 t2 main 5 BLOCKED 0.0 0.000 0:0.000 false false
12 DestroyJavaVM main 5 RUNNABLE 0.0 0.000 0:0.156 false false
2，执行“thread -b”命令，找出当前阻塞其他线程的线程，即造成死锁的罪魁祸首
[arthas@11596]$ thread -b"t1" Id=10 BLOCKED on java.lang.Object@26dee7d7 owned by "t2" Id=11at test.Deadlock.lambda$main$0(Deadlock.java:24)- blocked on java.lang.Object@26dee7d7- locked java.lang.Object@13a631ce <---- but blocks 1 other threads!at test.Deadlock$$Lambda$1/250421012.run(Unknown Source)at java.lang.Thread.run(Thread.java:748)
注：上面这个命令直接输出了 造成死锁的线程ID，和具体的代码位置，以及当前线程一共阻塞的线程数量：“<—- but blocks 1 other threads!“。
3，其他线程命令：
thread –all, 显示所有的线程；
thread id, 显示指定线程的运行堆栈；
thread –state：查看指定状态的线程，如：thread –state BLOCKED；
thread -n 3：展示当前最忙的前N个线程并打印堆栈；
Arthas
模拟死锁的场景
public class Deadlock {private static Object obj1 = new Object();private static Object obj2 = new Object();public static void main(String[] args) {new Thread(() -> {System.out.println("线程1执行");synchronized (obj1) {try {TimeUnit.SECONDS.sleep(1);} catch (InterruptedException e) {e.printStackTrace();}synchronized (obj2) {}}}, "t1").start();new Thread(() -> {System.out.println("线程2执行");synchronized (obj2) {synchronized (obj1) {}}}, "t2").start();System.out.println("执行完毕");}
}
通过thread命令定位
1，直接使用”thread“命令，输出线程统计信息。其中：BLOCKED 表示目前阻塞的线程数。
[arthas@11596]$ threadThreads Total: 26, NEW: 0, RUNNABLE: 8, BLOCKED: 2, WAITING: 4, TIMED_WAITING: 2, TERMINATED: 0, Internal threads: 10
ID NAME GROUP PRIORITY STATE %CPU DELTA_TIM TIME INTERRUPT DAEMON
2 Reference Handler system 10 WAITING 0.0 0.000 0:0.000 false true
3 Finalizer system 8 WAITING 0.0 0.000 0:0.000 false true
4 Signal Dispatcher system 9 RUNNABLE 0.0 0.000 0:0.000 false true
5 Attach Listener system 5 RUNNABLE 0.0 0.000 0:0.031 false true
14 arthas-timer system 5 WAITING 0.0 0.000 0:0.015 false true
17 arthas-NettyHttpTelnetBootstr system 5 RUNNABLE 0.0 0.000 0:0.015 false true
18 arthas-NettyWebsocketTtyBoots system 5 RUNNABLE 0.0 0.000 0:0.015 false true
19 arthas-NettyWebsocketTtyBoots system 5 RUNNABLE 0.0 0.000 0:0.015 false true
20 arthas-shell-server system 5 TIMED_WA 0.0 0.000 0:0.000 false true
21 arthas-session-manager system 5 TIMED_WA 0.0 0.000 0:0.000 false true
22 arthas-UserStat system 5 WAITING 0.0 0.000 0:0.000 false true
24 arthas-NettyHttpTelnetBootstr system 5 RUNNABLE 0.0 0.000 0:0.109 false true
25 arthas-command-execute system 5 RUNNABLE 0.0 0.000 0:0.015 false true
10 t1 main 5 BLOCKED 0.0 0.000 0:0.000 false false
11 t2 main 5 BLOCKED 0.0 0.000 0:0.000 false false
12 DestroyJavaVM main 5 RUNNABLE 0.0 0.000 0:0.156 false false
2，执行“thread -b”命令，找出当前阻塞其他线程的线程，即造成死锁的罪魁祸首
[arthas@11596]$ thread -b"t1" Id=10 BLOCKED on java.lang.Object@26dee7d7 owned by "t2" Id=11at test.Deadlock.lambda$main$0(Deadlock.java:24)- blocked on java.lang.Object@26dee7d7- locked java.lang.Object@13a631ce <---- but blocks 1 other threads!at test.Deadlock$$Lambda$1/250421012.run(Unknown Source)at java.lang.Thread.run(Thread.java:748)
注：上面这个命令直接输出了 造成死锁的线程ID，和具体的代码位置，以及当前线程一共阻塞的线程数量：“<—- but blocks 1 other threads!“。
3，其他线程命令：
thread –all, 显示所有的线程；
thread id, 显示指定线程的运行堆栈；
thread –state：查看指定状态的线程，如：thread –state BLOCKED；
thread -n 3：展示当前最忙的前N个线程并打印堆栈；